(1) Field of the Invention
The present invention relates to an apparatus for displaying images which controls a color hue of an image appearing on a screen of a cathode ray tube of a video equipment installed in a vehicle when a visual angle controlling filter such as a liquid crystal panel is installed in a front space of the screen of the CRT (Cathode Ray Tube) and a voltage is applied to the visual angle controlling filter.
(2) Background of the art
In a previously proposed image displaying apparatus, a louver type filter is disposed in front of a CRT (Cathode Ray Tube) so that a visible angle is limited to directions except a particular direction in order to prevent the images displayed on a screen of the CRT from viewing from a vehicular driver's seat during a drive of the vehicle in order to assure a safety driving.
When the vehicle runs, the louver type filter is mounted by a viewer in a front end of the CRT so that louvers in the filter cause a light directed to the driver's seat to be interrupted. However, since the louvers are designed so that the light toward passenger's seats except the driver's seat is not interrupted, thus the images on the CRT can be viewed from each of the passenger's seats.
In addition, when the vehicle stops and parks, the images on the CRT can be viewed from all vehicular seats including the driver's seat.
In another previously proposed image displaying apparatus, a liquid crystal panel is used as a visual angle controlling filter in place of the louver type filter since the louver type filter is inconvenient in its troublesome mounting and removal operations.
Controlling means applies a voltage to the liquid crystal panel during the run of the vehicle. The light from the CRT toward the driver's seat is thus interrupted. On the other hand, the light toward the passenger's seats except the driver's seat is not interrupted so as to enable viewing of the CRT from the passenger's seats. During the stop of the vehicle, the voltage is not applied to the liquid crystal panel so that the images on the screen of the CRT can be viewed from all directions.
However, since, in the latter previously proposed displaying apparatus, the liquid crystal panel has different light transmission factors according to a wavelength of the incident light during the application of voltage with the vehicle run, a color hue of the image on the screen of the CRT as viewed through the liquid crystal panel is varied so that the images on the screen of the CRT cannot clearly and correctly be viewed.
In addition, when the voltage application to the liquid crystal panel is turned off with the vehicle stopped, or vice versa (when the application is turned on with the vehicle started), the color hue is varied so that each viewer gives an unpleasant feeling.